Drafting attachment



March 3, 1931-. E. E. sHATTow 1,194,648

DBAFTING ATTACHMENT Filed July 21., 1928 l Unull/O' O I7, u? l 7 l jfl?? \7/ J0 l W55. .f a M ffpwgy Patented ltlar. 3, 'i931 l' Application filed July 2l,

This invention relates to irnprovernents in attachments for T-squares, and particularly to a drafting, attachment which coinprisesa combination scale and a French curve. The

principal object of the invention is to provide an attachment ofthi's type adapted' to be clidably inountedfupon the blade of the if-square and held in any adjusted position thereon, the lfrenchfcuiwe andscale being mounted upon the sliding blade clamp so Vas to be rotated to. any desired angle,

This invention is intended as an improvement upon myco-pending application, Serial Number 2??,254, iiledlt/ay 12, 1928.

panying'drawing, in whichy n Fig. 1 is a plan view of a drawing board with the drafting instrument applied thereto.

Fig. 2 is an enlarged fragmentary sectional view taken on the line 2-2of Fig. 1.

Fig, 3 is a view taken on the line 3 3 of -l is an enlarged fragmentary sectional view taken on the line 4% of Fig'. l.

Figv 5 is an enlarged fragmentary sectional view through the drawing board at onecorner thereof showing a portion of the rail held in spaced relation thereto and the removable clamp holding said rail, V

Lilie reference characters denote corresponding parts' throughout.

ri`he reference numeral 1 denotes a drawing board. Rernovably attached to the corners able fastening means 2, are the brackets 3 that carry the outwardly spaced rail Zl, picterablyround in cross section.

The reduced ends 5 ofthe rail in perforations in thexbracl the brackets are removed from the board, are

are received readily disengaged therefrom so that rails of diiferent lengths' can be releasably carried by the brackets, the length of there-.il corresponding to the distance betweenv rail l acting as the 'head of the square,.this

rEhe inventionis illustrated in the aecom-y ets and,V when t ie brackets which distance depends upon the reins DRAFTING .lTTfiCHE-NT ieee; seran No. esteseblade at one end being 'secured by rivets 7 to the clamp 8 that slidably engages-the rail fl,- said clamp being provided with the tightening screwA 9 whereby it may be held to any adjusted position upon said rail. Extending longitudinally of the blade 6 along its lateral edges and secured thereto by rivets 7 are the parallel spaced metal strips 10,'the

lateral edges of each strip being bevelled iii-f secured thereto by rivets 14 thel knob` 15 `that adjustably engages the'liat plate'lG formed to provide a scale and Frenchfcurvaa locking screw 'ljbeing provided to retain said knob 15 fand plate 16A in adjustedposition Ywhen desired. When the screw 17 is loose itY is obvious that the plate 16 isl rotatably mounted upon the slide 12.

The plate 16 is formed with a straight edge scale 18, with curves 19, 20, 21 formed alongV its opposite edge asl shown, with curved slots 22 and-with a longitudinally extendingy slot of one end thereof by screws, or other suit- 23 Pllll t0 its Straight edge, said slot re- 1' for use in connection with the graduations 26 of the sliding scale 11. Noparticular scale has been shown upon the sliding plate 11, up-V on the strips 10, nor upon the plate 16 but it isv to'be understood that any scales desired may be used. Y

rlhe French Y curves aboutits periphery and ,throughy the` slots 22, and straight lines along its straight edge which is graduated. Such straight lines curve and scale is used to draw can be made at predetermined distances apart, these distances being determined by the scale upon the strips l0.' The French curve can be used, in connection with the 5 strips, as a protractor. rl`he mark 25a may be used to note distance upon the strip from one end thereof to the said mark and if it isdesired to transfer the same to the straight edge of the French curve 10 this may be done by the sliding dog 25, which is for the purpose of indicating a certain scale mark or dimension on 18.

lhat isclaimed is l. A drafting board attachment comprising a straight edge, strips secured to the lateral edges cf said straight edge, the edges of said strips being undercut, a sliding scale hav ing its lateral edges beveled for snug sliding engagement between the adjacent edges of said strips, a slide mount-ed on .Said strips and having its side edges bent downwardly and inwardly for sliding engagement with the outer beveled edges of said strips and a rotary flat plate mounted on said slide, said flat plate, Y Y strips and sliding scaleA having marginal graduations.

2. A drafting board attachment comprising a straight edge, strips secured to the lat eral edges of said straight edge, a sliding scale removably received between said strips andv frictionally engaging the same, a slide mounted on said strips, a flat plate pivotally mounted on said slide and formed with a longitudinally extending slot parallel to one of its edges, and a dog movable over the slotted portion of said flat'plate, said flat plate, sliding scale and strips being provided with marginal graduations.

In testimony that IV claim the foregoing as 40 my own I have hereto aflixed my signature.

EMIL n sHATToW. 

